1. Technical Field
The present invention relates to a steering column for a vehicle, and in particular, to a steering column which is angularly and axially adjustable.
2. Description of the Prior Art
Steering columns which are angularly and axially adjustable are known. U.S. Pat. No. 4,649,769 discloses one such steering column which includes a pair of steering column members. The steering column members are axially movable (telescope) relative to one another and are supported by a bracket for angular movement (tilt) relative to the bracket. The steering column members may be locked in one of a plurality of relative axial positions and in one of a plurality of angular positions relative to the bracket. The steering column includes many cooperating parts. Manufacturing tolerances and wear of the cooperating parts may result in clearance between the cooperating parts. When the steering column is subjected to severe operating conditions, as is encountered in a heavy duty truck or off-road vehicle, clearance between the cooperating parts allows vibration and/or a feel of "looseness" in the steering column to be transmitted to the vehicle operator.
There have been attempts to reduce and eliminate the clearance between cooperating parts in a steering column. For example, U.S. Pat. No. 3,570,322 discloses a telescoping steering column having a hexagonal shaft supported in a tube by a plurality of wedges. Each of the wedges is disposed in a cooperating wedge-shaped channel in the tube. Springs bias the wedges in a direction so an angled surface of each wedge engages an angled surface of a channel to move the wedges radially inwardly and press against the shaft.
U.S. Pat. No. 4,619,548 discloses a telescoping steering column including an inner shaft received in an outer shaft. The outer shaft has internal splines for engaging external splines or the inner shaft. A rod having a tapered end portion is located within a bore in the inner shaft. When a nut is tightened on the rod, the rod moves axially within the inner shaft and expands the external spline against the internal spline to take up clearance.
U.S. Pat. No. 4,033,158 discloses a steering column supported for tilting movement. The steering column includes a rod having an end portion receivable in one of a plurality of notches in a plate. The end portion of the rod has a angled surface for engaging a corresponding angled surface of the one notch. A spring biases the rod toward the plate and the cooperating angled surfaces urge the rod to move in a direction transversely relative to the longitudinal central axis of the rod and against another surface of the notch. Clearance between the end portion of the rod and the notch is, thus, taken up.